We plan to study: (1) The role of the subunits of phosphorylase kinase in catalysis and regulation and the function of Ca ions in this enzyme. (2) The action of phosphorylase kinase on synthetic peptide substrates to establish its specificity requirements and mechanism of action. (3) Phosphorylase phosphatase action and determine whether this enzyme is a metalloprotein. (4) The role of the amino terminal segment of glycogen phosphorylase in regulation by chemical and immunochemical methods. Peptides will be used in complementation studies. (5) The synthesis of pyridoxal derivatives. These will be used to test some possible mechanisms for the involvement of pyridoxal phosphate in phosphorylase catalysis. (6) Action of peptide inhibitors and purine derivatives on cyclic AMP dependent protein kinase.